Electrolyte and method for deposition of matte metal layer

ABSTRACT

This invention relates to an electrolyte as well as a method for the deposition of a matte metal layer on a substrate surface, where the matte metal layer is V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, In, Sn, Sb, Te, Re, Pt, Au, TI, Bi, or an alloy thereof, and there is a halogenide, sulphate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron to facilitate deposition of a smooth and even layer with much lower deposition metal requirements.

FIELD OF THE INVENTION

This invention relates to an electrolyte as well as a method for the deposition of a matte metal layer on a substrate surface. In particular, the invention relates to an electrolyte which has a low concentration of the deposition metal and a method to deposit a matt metal layer by using such electrolytes.

BACKGROUND OF THE INVENTION

In general, it is the intention when depositing metal layers on substrate surfaces to gain a plain and glossy metal layer on the substrate surface. The metal layer deposited may have functional properties, which properties can optimize the substrate surface for the later proposal, or decorative effects should be obtained. According to the intended use of the substrate, sometimes it is preferred to have a non-glossy, matte or so-called pearl bright metal layer on the substrate surface. On one side, this intention can be based on the optical appearance of the deposit, on the other side matte or so-called pearl bright deposits have specific technical properties, like for example to be non-glare, which properties may be desirable for technical or decorative use. The application area for such a matte or pearl bright metal layers is, for example, jewelry industry, fitting industry, automotive industry, as well as optical or fine mechanical industry. Especially in these areas non-glare metal layers are desired. In the area of jewelry industry, the deposition of matte or pearl bright metal layers of non-allergic or low allergic metals is requested. The same is true for the application of matte or pearl bright metal layers in the area of kitchen machinery and kitchen implements.

In the field of optical or fine mechanical industry the deposition of matte or pearl bright metal layers of different metals is of interest due to the different features which come along with the different metals, thus the substrate surface can be adapted to the later technical use. In this concern, for example, the ductility, the hardness, the corrosion resistance, or comparable mechanical properties of the substrate surface can be optimized.

The international patent application WO 2007/076898 discloses an electrolyte as well as a method for the deposition of matte metal layers, especially of the metals vanadium, chrome, manganese, iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, silver, indium, tin, antimony, tellurium, rhenium, platinum, gold, thallium, bismuth, or alloys of these. For the deposition of these metals on a substrate surface, according to WO 2007/076898, which is incorporated as reference, an emulsion and/or dispersion is formed in the electrolyte by addition of an emulsion agent and/or dispersion agent, or a wetting agent.

A drawback of the electrolyte as well as the method known from the state of the art is that sometimes it is difficult to gain even deposits on the substrate surface. Thus, it is the object of this invention to optimize the electrolyte as well as the method known from the state of the art.

SUMMARY OF THE INVENTION

Briefly, therefore, the invention in one aspect is directed to an electrolytic composition for the deposition of a matte layer of metal or alloy on a substrate surface, comprising deposition metal ions selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, In, Sn, Sb, Te, Re, Pt, Au, Tl, Bi, and combinations thereof for depositing a metal or alloy of the foregoing; at least one halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron; and one or more of a dispersion former selected from the group consisting of unsubstituted polyalkylene oxide, substituted polyalkylene oxide, a derivative of a substituted or unsubstituted polyalkylene oxide, a fluorinated wetting agent, a perfluorinated wetting agent, a quaternary amine, or a quaternary amine substituted with polyalkylene oxide.

In another aspect, the invention is directed to an electrolytic composition for the deposition of a matte layer of metal or alloy on a substrate surface, comprising deposition metal ions selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, In, Sn, Sb, Te, Re, Pt, Au, Tl, Bi, and combinations thereof for depositing a metal or alloy of the foregoing; at least one halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron; one or more of a dispersion former selected from the group consisting of unsubstituted polyalkylene oxide, substituted polyalkylene oxide, a derivative of a substituted or unsubstituted polyalkylene oxide, a fluorinated wetting agent, a perfluorinated wetting agent, a quaternary amine, or a quaternary amine substituted with polyalkylene oxide; and a surface active wetting agent selected from the group consisting of alkyl sulfates, sulfo-succinic acid, and betaines.

The invention is also directed to a method for depositing a matte layer on a surface of a substrate, the method comprising exposing the surface of the substrate to an electrolytic plating composition according as described above; and conducting a current between the substrate and an anode to thereby deposit the matte layer on the surface of the substrate.

Another aspect of the invention is a more specific method for depositing a matte nickel layer on a surface of a substrate, the method comprising exposing the surface of the substrate to an electrolytic nickel plating composition comprising at least about 10 g/L nickel ions and an auxiliary metal ion selected from the group consisting of sodium, potassium, magnesium, aluminum, boron, or combinations thereof, wherein a weight ratio of auxiliary metal ions to nickel metal ions is at least about 0.8:1; and conducting a current between the substrate and an anode to thereby deposit the matte nickel layer on the surface of the substrate.

In another embodiment the invention is directed to a method for depositing a matte nickel layer on a surface of a substrate, the method comprising exposing the surface of the substrate to an electrolytic nickel plating composition comprising at least about 40 g/L nickel ions and an auxiliary metal ion selected from the group consisting of sodium, potassium, magnesium, aluminum, boron, or combinations thereof, wherein a weight ratio of auxiliary metal ions to nickel metal ions is at least about 0.2:1; and conducting a current between the substrate and an anode to thereby deposit the matte nickel layer on the surface of the substrate.

The invention is further directed to a method for depositing a matte cobalt-tin alloy layer on a surface of a substrate, the method comprising exposing the surface of the substrate to an electrolytic cobalt-tin alloy plating composition comprising at least about 10 g/L cobalt ions, at least about 10 g/L tin ions, and an auxiliary metal ion selected from the group consisting of sodium, potassium, magnesium, aluminum, boron, or combinations thereof, wherein a weight ratio of auxiliary metal ions to sum of the cobalt metal ions and the tin metal ions is at least about 0.2:1; and conducting a current between the substrate and an anode to thereby deposit the matte cobalt-tin alloy layer on the surface of the substrate.

Other objects and features will be in part apparent and in part pointed out hereinafter.

DESCRIPTION OF THE EMBODIMENT(S) OF THE INVENTION

This application claims priority to European application 08012262.5, filed Jul. 8, 2008, the entire disclosure of which is incorporated by reference.

The present invention is directed to an electrolyte for the deposition of a matte metal layer of a metal selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, In, Sn, Sb, Te, Re, Pt, Au, Tl, Bi, or an alloy of any these metals on a substrate surface. The electrolyte of the present invention therefore comprises a source of plating metal ions selected from the group consisting of vanadium ions, chromium ions, manganese ions, iron ions, cobalt ions, nickel ions, copper ions, zinc ions, ruthenium ions, rhodium ions, palladium ions, silver ions, indium ions, tin ions, antimony ions, tellurium ions, rhenium ions, platinum ions, gold ions, thallium ions, bismuth ions, and any combination of ions from among those listed.

In some embodiments, the source of plating metal ions is selected from the group consisting of vanadium ions, chromium ions, manganese ions, iron ions, cobalt ions, nickel ions, copper ions, ruthenium ions, rhodium ions, palladium ions, silver ions, indium ions, tin ions, antimony ions, tellurium ions, rhenium ions, platinum ions, gold ions, thallium ions, bismuth ions, and any combination of ions from among those listed. The electrolyte is therefore suitable for depositing a matte metal layer of a metal selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, In, Sn, Sb, Te, Re, Pt, Au, Tl, Bi, or an alloy of any these metals on a substrate surface.

In some embodiments, the source of plating metal ions is selected from the group consisting of iron ions, cobalt ions, nickel ions, copper ions, zinc ions, tin ions, silver ions, and any combination of ions from among those listed. The electrolyte is therefore suitable for depositing a matte metal layer of a metal selected from the group consisting of Fe, Co, Ni, Cu, Zn, Sn, Ag, or an alloy of any these metals on a substrate surface. In certain preferred embodiments, the source of plating metal ions is selected from the group consisting of iron ions, cobalt ions, nickel ions, copper ions, tin ions, silver ions, and any combination of ions from among those listed. The electrolyte is therefore suitable for depositing a matte metal layer of a metal selected from the group consisting of Fe, Co, Ni, Cu, Sn, Ag, or an alloy of any these metals.

In each of the foregoing embodiments, “alloy” encompasses three distinct embodiments, namely, one of the listed metals alloyed with one or more other of the listed metals; one of the listed metals alloyed with one or more non-listed metals; and one of the listed metals alloyed with one or more other of the listed metals and one or more non-listed metals. Accordingly, with respect to the metal ions, in some embodiments the composition includes only one or more of the listed ions; and in other embodiments optionally in combination with non-listed ions. That is, some embodiments specifically exclude other metal ions not listed, and other embodiments do not so exclude.

The electrolyte of the present invention is characterized in that the electrolyte comprises a relatively lower concentration of plating metal ions compared to conventional matte layer plating electrolytes. If everything else about the electrolyte is equal, having a lower concentration of the plating metal ions results in an electrolyte having a lower density. Generally speaking, such a lower density composition tends to be unable to reliably deposit a matte or pearl bright metal layer. Rather, the layer tends to be glossy or semi-glossy. The electrolyte of the present invention therefore further comprises at least one halogenide, sulfate, or sulfonate of an element selected from the group consisting of sodium, potassium, aluminum, magnesium, or boron. By adding a halogenide, sulfate, or sulfonate salt of sodium, potassium, aluminum, magnesium, or boron, the density of the electrolyte is established at or near the density of a conventional electrolyte that comprises a much higher concentration of plating metal ions.

In some embodiments, the additive employed partially instead of plating metal ions (as compared to a conventional matte electrolyte) and which maintains the density of the electrolyte at or near that of a conventional electrolyte comprising a high plating metal ion concentration may be selected from among the methanesulfonates of sodium, potassium, or magnesium and hydrates thereof. These are referred to herein as density increasing compounds in that incorporating them into the electrolyte results in a greater density than if they had not been employed. In some embodiments, aluminum sulfates and hydrates thereof are preferred. In some embodiments, sodium sulfates and hydrates thereof are preferred. In some embodiments, magnesium sulfates and hydrates thereof are preferred. In some embodiments, boron tetrafluoride is used. In some embodiments, a combination of aluminum sulfates and hydrates thereof and boron tetrafluoride is used.

In a preferred embodiment, the density increasing compound in the inventive electrolyte is sodium sulfate and hydrates thereof, magnesium sulfate and hydrates thereof, aluminum sulfate and hydrates thereof, or a combination of these three salts.

Surprisingly, it was found that the addition of soluble compounds of heavy cations, especially of an alkaline halogenide or alkaline earth halogenide, an alkaline sulfate or alkaline earth sulfate, or an alkaline sulfonate or alkaline earth sulfonate as well as aluminum sulfate, aluminum chloride, or boron tetrafluoride, alone or in combination, is capable to overcome the drawbacks known from the state of the art, specifically by allowing the plating of matte or pearl bright metal layers from electrolytes having relatively low concentrations of plating metal ions.

According to the invention, the electrolyte comprises a salt that maintains the density of the electrolyte of the invention at a concentration such that the cation of said salt is present in the electrolyte of the invention in a range of from 10% to 100% by weight of the concentration of the metal to be deposited. Preferably, the salt is added to the electrolyte of the present invention in a concentration such that the cation of said salt is present in a range between 20% to 60% by weight of the concentration of the metal to be deposited.

In general, the concentration of the salt of the auxiliary metal ion is such that the auxiliary metal ion is present in a weight ratio of the auxiliary metal ion to the plating metal ion of at least about 0.2:1, at least about 0.4:1, at least about 0.6:1, or even at least about 0.8:1. In some embodiments, the auxiliary metal ion is present in a weight ratio of the auxiliary metal ion to the plating metal ion of between about 0.10:1 to 1.3:1, such as between about 0.10:1 to 1:1, preferably between about 0.2:1 and about 0.6:1. By “auxiliary metal” it is meant the type of ions, such as sodium, potassium, aluminum, magnesium, or boron, that is not reduced or is not substantially reduced into metal and thus does not become incorporated in the matte or pearl bright metal layer on the substrate in any more than a trace amount, i.e., less than 1 atomic %, less than 0.5 atomic %, preferably less than 0.1 atomic %. The auxiliary metal ion is incorporated into the electrolyte of the present invention to substantially maintain the density of the solution compared to a conventional electrolyte that generally comprises a high concentration of plating metal ion, which enable deposition of matte or pearl bright layers in electrolytes having relatively low concentrations of plating metal ions.

For example, in an electrolytic nickel plating bath, such as a Watts type bath, the weight ratio of the auxiliary metal ion to the nickel ion may be at least about 0.2:1, such as at least about 0.4:1, at least about 0.6:1, or even at least about 0.8:1, such as about 0.9:1, about 1:1, about 1.1:1, about 1.2:1, or even about 1.3:1. In view thereof, the weight ratio of the auxiliary metal ion to the nickel ion may range from about 0.2:1 to about 1.3:1, such as between about 0.6:1 to about 1.2:1. By incorporating an auxiliary metal ion such as sodium, potassium, aluminum, magnesium, or boron and more preferably magnesium into an electrolytic nickel plating bath, the concentration of nickel ion is lower in comparison to a conventional electrolytic matte nickel plating bath.

As a general proposition, in some preferred embodiments, the nickel concentration is generally at least about 10 g/L, at least about 15 g/L, at least about 20 g/L, at least about 30 g/L, at least about 40 g/L, or even at least about 45 g/L. The nickel concentration is generally less than about 80 g/L, about 75 g/L, or less than about 60 g/L. In some embodiments, the nickel ion concentration is between about 10 g/L and about 80 g/L, between about 10 g/L and about 70 g/L, between about 10 g/L and about 60 g/L, or between about 15 g/L and about 50 g/L. In general, the auxiliary metal ion concentration is at least about 10 g/L, at least about 15 g/L, least about 20 g/L, or even at least about 25 g/L. In some embodiments, the nickel ion concentration is at least about 10 g/L and the weight ratio of auxiliary metal ions to nickel ions is at least about 0.8:1, at least about 1:1, or at least about 1.2:1. In some embodiments, the nickel ion concentration is at least about 40 g/L and the weight ratio of auxiliary metal ions to nickel ions is at least about 0.2:1, at least about 0.4:1, or at least about 0.6:1. Such an electrolytic nickel plating composition having a nickel ion concentration within the above described ranges and an auxiliary metal ion in a concentration sufficient to yield the above described weight ratios has been shown to deposit matte and pearl bright nickel layers.

In another embodiment, an electrolytic cobalt-tin alloy plating bath may comprise a weight ratio of the auxiliary metal ion to the total plating ion (i.e., sum of cobalt ion and tin ion) of at least about 0.2:1, such as at least about 0.4:1, at least about 0.6:1, or even at least about 0.8:1, such as about 0.9:1, about 1:1, about 1.1:1, about 1.2:1, or even about 1.3:1. In view thereof, the weight ratio of the auxiliary metal ion to the sum of the cobalt ion and tin ion may range from about 0.2:1 to about 1:1, such as between about 0.2:1 to about 0.8:1.

By incorporating an auxiliary metal ion such as sodium, potassium, aluminum, magnesium, or boron and more preferably aluminum, sodium, or a combination of the two into an electrolytic cobalt-tin alloy plating bath, the concentration of cobalt ion and tin ion may be lower compared to a conventional electrolytic cobalt-tin alloy plating bath. The cobalt concentration is generally at least about 10 g/L, about 15 g/L, or even about 20 g/L, and the cobalt concentration is generally less than about 80 g/L, about 75 g/L, or less than about 60 g/L. The cobalt ion concentration may be between about 20 g/L and about 70 g/L, or between about 30 g/L and about 60 g/L. The tin concentration is generally at least about 10 g/L, about 15 g/L, or even about 20 g/L, and the tin concentration is generally less than about 60 g/L, about 50 g/L, or less than about 40 g/L. The tin ion concentration may be between about 10 g/L and about 40 g/L, or between about 15 g/L and about 30 g/L. Such an electrolytic cobalt-tin alloy plating composition having cobalt ion and tin ion concentrations within the above described ranges and an auxiliary metal ion in a concentration sufficient to yield the above described weight ratios has been shown to deposit matte and pearl bright cobalt-tin alloy layers.

The foregoing concentrations of Ni, Co, and/or Sn similarly apply to plating compositions of the invention which employ the other metals from among V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, In, Sn, Sb, Te, Re, Pt, Au, Tl, Bi, and alloys thereof as the plating metal.

By increasing the density of the electrolyte, the cloud point is exceeded, which effect is to be avoided by normal plating electrolytes, but here leads to the desired matte effect of the deposited metal layer. The addition of the mentioned inert compounds (i.e., the Na, K, Al, Mg, and/or B compounds, or so-called density increasing compounds) which do not comprise any depositable metal cations increases the density so that a matte metal layer is deposited even at a very low concentration of plating metal in the electrolyte. Preferably, the density is similar to a conventional solution for depositing matte or pearl bright layers. Therefore, the density of the electrolyte of the present invention is preferably between about 85% to about 115% of the density of a conventional, higher plating metal ion concentration electrolyte, even though the electrolyte of the present invention has a much lower concentration of the plating metal ion. That is, the inert metal salt contributes to density, so that the desired density is achieved even without the higher concentration of plating metal. Preferably, the density is between about 95% and about 105% of such a conventional electrolyte. Higher densities generally contribute to lower cloud points. The electrolyte of the present invention exceeds the cloud point, which is useful for achieving an emulsion or dispersion and thus the matte or pearl bright appearance of the final plated layer.

Stated another way, the inclusion of the inert metal salt of Na, K, Al, Mg, or B yields a composition which overall has a cloud point below the operating temperature of the electrolytic composition. That way, at operating temperature, the cloud point is exceeded, which is useful for achieving an emulsion or dispersion and thus the matte or pearl bright appearance of the final plated layer, in accordance with this invention.

The electrolyte of the present invention further comprises a dispersion or emulsion forming substance selected from among substituted or unsubstituted polyalkylene oxides, derivatives of substituted or unsubstituted polyalkylene oxides, fluorinated or perfluorinated wetting agents, or quaternary ammonium compounds substituted with a polyalkalylene oxide. Those substances are suitable for forming an emulsion and/or dispersion in the electrolyte.

Dispersion or emulsion forming substances suitable for use in the electrolyte of the present invention include substituted or unsubstituted polyalkylene oxide and derivatives of substituted or unsubstituted polyalkylene oxides. Useful polyalkylene oxide type surfactants include polyethylene glycols having average molecular weights ranging from 5000 to 100,000 g/mol. Commercially available polyethylene glycols are sold under the Pluriol® trade name from BASF. Additionally polyalkylene oxide type surfactants include polypropylene glycols having average molecular weights ranging from 500 to 20,000 g/mol. Commercially available polypropylene glycols are sold under the Pluriol® trade name from BASF. Also useful are polypropylene glycol/polyethylene glycol co-polymers, such as Pluronic® PE and RPE, also available from BASF. These typically have molecular weights ranging from 1000 to 5000 g/mol. Substituted or unsubstituted polyalkylene oxide and derivatives thereof may be added to the electrolyte in a concentration range from 0.1 mg/L to 10 g/L.

Dispersion or emulsion forming substances also include quaternary amines and quaternary amines substituted with polyalkylene oxide. Quaternary amines substituted with polyalkylene oxide include those sold under the trade name Ethoquad® type, available from Akzo Nobel. Also useful are quaternary amine surfactants sold under the trade names Hyamine and Barquat®. Barquat® quaternary amines include Barquat® MB-50 and Barquat® MB-80, available from Lonza Chemical. Quaternary amine and quaternary amines substituted with polyalkylene oxide dispersion or emulsion forming substances may be added to the electrolyte of the present invention in a concentration from 0.1 mg/L to 1 g/L, preferably from 1 mg/L to 100 mg/L.

The dispersion or emulsion forming additives may be incorporated into the electrolyte as a commercially available package of additives, such as PEARLBRITE®, available from Enthone Inc. The PEARLBRITE® package may include the dispersion or emulsion forming additives as well as carrier additives and uniformity enhancing additives as are known in the art. The carrier additive may be present in the electrolyte from about 1 g/L to about 15 g/L, such as from 2 g/L to about 10 g/L, such as about 5 g/L. One such carrier additive is sodium saccharinate. Additives for enhancing the uniformity of the deposit typically are complexing agents which are added to shift the standard reduction potentials of the various metals into a similar range. Complexing agents are typically added to the electrolyte in a concentration range from 50 to 200 g/L, such as from 70 to 140 g/L. Complexing agents include gluconate, cyanide, citric acid, and others as are known in the art.

It was surprisingly found that the addition of a surface active wetting agent to the inventive electrolyte is possible. The addition of a surface active wetting agent further supports the even deposition of metal layers. To the electrolytes known from the state of the art the addition of surface active wetting agents was not possible since those surface active wetting agents would influence the formation of an emulsion and/or dispersion in the electrolyte, thereby influencing the matte or pearl bright effect of the electrolyte. If surface active wetting agents were added to the electrolytes known from the state of the art, the deposited metal layers turned to be glossy instead of being non-glare.

In the inventive electrolyte, the addition of surface active wetting agents is possible without influencing the matte effect of the electrolyte.

Surface active wetting agents which can be added to the inventive electrolyte may be a wetting agent of the group consisting of alkyl sulfates, sulfosuccinic acid, and betaines. Alkyl sulfates generally include those having hydrocarbon chains having from 8 to about 20 carbon atoms, typically from 12 to 14 carbon atoms, such as decyl sulfates, dodecyl sulfates, tetradecyl sulfates, hexadecyl sulfates, and octadecyl sulfates, typically charged balances with sodium ions, potassium ions, magnesium ions, and ammonium ions, among others.

Sulfosuccinates useful for the electrolyte are of the type available from Akzo Nobel. Sulfosuccinates typically have fatty hydrocarbyl chains having from 8 to 20 carbon atoms, typically from 8 to 12 carbon atoms that form esters and/or may be charged balances with sodium ions, potassium ions, magnesium ions, and ammonium ions, among others.

The surface active wetting agent may be comprised in the inventive electrolyte in a concentration between 0.01 mol/L and 100 mol/L, preferably between 0.1 mol/L and 10 mol/L.

In terms of the method, the object of the invention is solved by a method for the electrolytic deposition of a matte metal layer on a substrate surface, which matte metal layer is deposited from an electrolyte forming an emulsion and/or dispersion by conducting a current between a cathodic contacted substrate surface and an anode, which method is characterized in that 10 to 50% by weight of the metal to be deposited comprised in the electrolyte is substituted by at least on density increasing halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron. The current density may range from 0.1 to 100 A/dm². The current density depends upon empirical conditions, e.g., the plating metal ion. Plating occurs by connecting the surface of the substrate, which acts as the cathode to a power supply and connecting an anode, suitably an insoluble anode to the power supply and passing a current between the cathode (substrate) and the anode. In some embodiments, the electrolyte of the present invention is useful for depositing a matte nickel layer at a current density between about 2 and about 7 A/dm². In general, deposition progresses until the plated metal layer has a thickness generally between about 2 micrometers and about 20 micrometers, but thinner and thicker plated metal layers are within the scope of the present invention.

It is the inventive idea to substitute some of the concentration of the metal to be deposited in the electrolyte by a density increasing compound, thereby reducing the concentration of the metal to be deposited and increasing the density of the electrolyte.

By doing so, on one hand, due to the less amount of metal to be deposited in the electrolyte an economic benefit is gained, since less deposition metal has to be used to formulate the electrolyte. On the other hand, due to the addition of an alkali compound and/or alkaline earth compound, the density of the electrolyte is increased, which leads to a more even deposition of the metal on the substrate surface. Furthermore, it was found that due to the increased density of the electrolyte, the addition of a surface active wetting agent is possible without influencing the matte appearance of the deposited metal layer in an unintended way.

Having described the invention in detail, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.

EXAMPLES

The following non-limiting examples are provided to further illustrate the present invention.

Example 1

A Watts-type electrolyte of the invention was prepared comprising:

190 g/L nickel sulfate hexahydrate (NiSO₄.6H₂O)

40 g/L boric acid

30 g/L nickel chloride hexahydrate (NiCl₂.6H₂O)

5 g/L sodium saccharinate and

300 g/L magnesium sulfate heptahydrate (MgSO₄.7H₂O)

3 mg/L PEG 10000

The above electrolyte of the invention had a density of about 1.322 g/cm³. The nickel ion concentration of the electrolyte of the invention was about 49.83 g/L. The magnesium ion concentration was about 29.59 g/L. Accordingly, the weight ratio of magnesium ion to nickel ion was about 0.6:1.

A matte nickel layer was deposited from this electrolyte in 10 minutes at a temperature of 52° C. and a current density of 5 A/dm². The pH-value of the electrolyte was about 4.2. The substrate to be plated was moved through the electrolyte at a speed of 2 m/min. The structure of the matte nickel layer deposited was identical to the structure of a matte nickel layer deposited from a comparative electrolyte comprising 3 mg/L of a polyethyleneglycol having an average molecular weight of 10,000 g/mol, which electrolyte contained:

440 g/L nickel sulfate hexahydrate (NiSO₄.6H₂O)

40 g/L boric acid

30 g/L nickel chloride hexahydrate (NiCl₂.6H₂O)

5 g/L sodium saccharinate and

3 mg/L PEG 10000.

The comparative electrolyte had a density of about 1.322 g/cm³. The nickel ion concentration of the comparative electrolyte was about 105.65 g/L.

Example 2

A Watts-type electrolyte of the invention was prepared comprising:

190 g/L nickel sulfate hexahydrate (NiSO₄.6H₂O)

40 g/L boric acid

30 g/L nickel chloride hexahydrate (NiCl₂.6H₂O)

5 g/L sodium saccharinate and

300 g/L magnesium sulfate heptahydrate (MgSO₄.7H₂O)

6 mg/L BARQUAT® MB-80

The above electrolyte of the invention had a density of about 1.322 g/cm³. The nickel ion concentration of the electrolyte of the invention was about 49.83 g/L. The magnesium ion concentration was about 29.59 g/L. Accordingly, the weight ratio of magnesium ion to nickel ion in the electrolyte of the invention was about 0.6:1.

A matte nickel layer was deposited from the above electrolyte in 10 minutes at a temperature of 52° C. and a current density of 5 A/dm². The pH-value of the electrolyte was about 4.2. The substrate to be plated was moved through the electrolyte at a speed of 2 m/min. The structure of the matte nickel layer deposited was identical to the structure of a matt nickel layer deposited from a comparative electrolyte comprising 6 mg/L BARQUAT® MB-80, which electrolyte contained:

440 g/L nickel sulfate hexahydrate (NiSO₄.6H₂O)

40 g/L boric acid

30 g/L nickel chloride hexahydrate (NiCl₂.6H₂O)

5 g/L sodium saccharinate and

6 mg/L BARQUAT® MB-80.

The comparative electrolyte had a density of about 1.322 g/cm³, and a nickel ion concentration of about 105.65 g/L.

Example 3

An electrolyte of the invention for depositing a tin-cobalt alloy was prepared comprising:

120 g/L sodium gluconate

50 g/L cobalt(II) sulfate heptahydrate (CoSO₄.7H₂O)

25 g/L tin(II) sulfate (SnSO₄)

260 g/L sodium sulfate decahydrate (Na₂SO₄.10H₂O) and

1 mg/L PEG 35000

The above electrolyte of the invention had a density of about 1.288 g/cm³. In the above electrolyte of the present invention, the cobalt ion concentration was about 10.48 g/L, and the tin ion concentration was about 13.82 g/L. The sodium ion concentration was about 18.55 g/L. Accordingly, the weight ratio of sodium ion to plating metal ion (sum of cobalt ion and tin ion) was about 0.76:1.

A very fine matte tin-cobalt layer was deposited from the above electrolyte in 5 minutes at a temperature of 45° C. and a current density of 0.5 A/dm². The pH-value of the electrolyte was about 8.4 and the substrate to be plated was moved through the electrolyte at a speed of 2 m/min. The very fine matte layer deposited from the above electrolyte was identical to a layer deposited from a comparative electrolyte comprising:

120 g/L sodium gluconate

100 g/L cobalt (II) sulfate heptahydrate (CoSO₄.7H₂O)

50 g/L tin(II) sulfate (SnSO₄)

1 mg/L PEG 35000.

The comparative electrolyte had a density of about 1.225 g/cm³. In the comparative electrolyte, the cobalt ion concentration was about 20.96 g/L, and the tin ion concentration was about 27.64 g/L.

The above Examples 1, 2, and 3 clearly show that the inventive addition of an alkali compound or alkaline earth compound to an electrolyte composition known from the state of the art enables use of a lower plating metal concentration in the electrolyte, without influencing the plating result. This enables plating electrolytes having a very low concentration of plating metal which gives great economic benefit.

Example 4

An electrolyte of the invention for depositing a nickel layer was prepared comprising:

225 g/L nickel sulfate hexahydrate (NiSO₄.6H₂O)

50 g/L nickel chloride hexahydrate (NiCl₂.6H₂O)

40 g/L boric acid

225 g/L magnesium sulfate heptahydrate (MgSO₄.7H₂O)

2.6 g/L sodium benzoic acid sulfonimide

1.5 mg/L polyethylenglycol-methylether and

1.8 mg/L sodium-2-propen-sulfonate

The above electrolyte of the invention had a density of about 1.303 g/cm³. The nickel ion concentration in the electrolyte of the invention was about 50.21 g/L. The magnesium ion concentration was about 22.19 g/L. Accordingly, the weight ratio of magnesium ion to nickel ion in the electrolyte of the invention was about 0.4:1.

A matte nickel layer was deposited from the above electrolyte on a substrate surface in 10 min. at a current density of 5 A/dm² and a temperature of 55° C., which layer has the same properties than a layer deposited under the same conditions from a comparative electrolyte comprising 450 g/L nickel sulfate hexahydrate (NiSO₄.6H₂O) and no magnesium sulfate heptahydrate (MgSO₄.7H₂O). The comparative electrolyte had a density of about 1.326 g/cm³, and a nickel ion concentration of about 112.82 g/L.

Example 5

An electrolyte of the invention for depositing a tin-cobalt alloy was prepared comprising:

120 g/L sodium gluconate

50 g/L cobalt(II) sulfate heptahydrate (CoSO₄.7H₂O)

25 g/L tin(II) sulfate (SnSO₄)

120 g/L aluminum sulfate octadecahydrate

(Al₂(SO₄)₃.18H₂O) and

1 mg/L PEG 35000

The above electrolyte of the invention had a density of about 1.235 g/cm³. In the above electrolyte of the present invention, the cobalt ion concentration was about 10.48 g/L, and the tin ion concentration was about 13.82 g/L. The aluminum ion concentration was about 4.86 g/L. The weight ratio of aluminum ion to plating metal ion (sum of cobalt and tin ions) was about 0.2:1.

A very fine matte tin-cobalt layer was deposited from the above electrolyte in 5 minutes at a temperature of 45° C. and a current density of 0.5 A/dm². The pH-value of the electrolyte was about 8.4 and the substrate to be plated was moved through the electrolyte at a speed of 2 m/min. The very fine matte layer deposited from the above electrolyte was identical to a layer deposited from a comparative electrolyte which contained:

120 g/L sodium gluconate

100 g/L cobalt(II) sulfate heptahydrate (CoSO₄.7H₂O)

50 g/L tin(II) sulfate (SnSO₄)

1 mg/L PEG 35000.

The comparative electrolyte had a density of about 1.225 g/cm³. In the comparative electrolyte, the cobalt ion concentration was about 20.96 g/L, and the tin ion concentration was about 27.64 g/L.

The above embodiments clearly show that the inventive addition of a density increasing compound to an electrolyte composition known from the state of the art enables the reduction of the plating metal concentration in the electrolyte, without influencing the plating result. This enables plating electrolytes having a very low concentration of plating metal which gives great economic benefit.

When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above compositions and processes without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense. 

1-36. (canceled)
 37. An electrolytic composition for the deposition of a matte layer of metal or alloy on a substrate surface, comprising: deposition metal ions selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, In, Sn, Sb, Te, Re, Pt, Au, Tl, Bi, and combinations thereof for depositing a metal or alloy of the foregoing; at least one halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron; wherein the sodium, potassium, aluminum, magnesium, and/or boron is in a concentration within the range between 10% and 100% by weight of the concentration of the deposition metal ions; and one or more of a dispersion former selected from the group consisting of unsubstituted polyalkylene oxide, substituted polyalkylene oxide, a derivative of a substituted or unsubstituted polyalkylene oxide, a fluorinated wetting agent, a perfluorinated wetting agent, a quaternary amine, or a quaternary amine substituted with polyalkylene oxide.
 38. The electrolytic composition of claim 37 wherein the deposition metal ions are selected from the group consisting of Fe, Co, Ni, Cu, Sn, Ag, and combinations thereof.
 39. The electrolytic composition according to claim 37 wherein the at least one halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron is one or more from the group consisting of sodium methanesulfonate and hydrates thereof, potassium methanesulfonate and hydrates thereof, magnesium methanesulfonate and hydrates thereof, aluminum sulfate and hydrates thereof, or a boron tetrafluoride.
 40. The electrolytic composition according to claim 37 wherein the at least one halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron is one or more from the group consisting of aluminum sulfates and hydrates thereof, sodium sulfates and hydrates, and magnesium sulfates and hydrates thereof, and any combination thereof.
 41. The electrolytic composition according to claim 38 wherein the at least one halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron is one or more from the group consisting of sodium methanesulfonate and hydrates thereof, potassium methanesulfonate and hydrates thereof, magnesium methanesulfonate and hydrates thereof, aluminum sulfate and hydrates thereof, or a boron tetrafluoride.
 42. The electrolytic composition according to claim 38 wherein the at least one halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron is one or more from the group consisting of aluminum sulfates and hydrates thereof, sodium sulfates and hydrates, and magnesium sulfates and hydrates thereof, and any combination thereof.
 43. The electrolytic composition according to claim 38 wherein the deposition metal ions comprise nickel ions and the sodium, potassium, aluminum, magnesium, and/or boron is present in a concentration such that the weight ratio of the sodium, potassium, aluminum, magnesium, and/or boron to the nickel ions is at least about 0.4:1.
 44. The electrolytic composition according to claim 38 wherein the deposition metal ions comprise cobalt ions and tin ions and the sodium, potassium, aluminum, magnesium, and/or boron is present in a concentration such that the weight ratio of the sodium, potassium, aluminum, magnesium, and/or boron to the sum of the cobalt ions and tin ions is at least about 0.4:1.
 45. The electrolytic composition of claim 1 further comprising a surface active wetting agent selected from the group consisting of alkyl sulfates, sulfo-succinic acid, and betaines.
 46. A method for depositing a matte layer on a surface of a substrate, the method comprising: exposing the surface of the substrate to an electrolytic plating composition comprising: deposition metal ions selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, In, Sn, Sb, Te, Re, Pt, Au, Tl, Bi, and combinations thereof for depositing a metal or alloy of the foregoing; at least one halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron; and one or more of a dispersion former selected from the group consisting of unsubstituted polyalkylene oxide, substituted polyalkylene oxide, a derivative of a substituted or unsubstituted polyalkylene oxide, a fluorinated wetting agent, a perfluorinated wetting agent, a quaternary amine, or a quaternary amine substituted with polyalkylene oxide; and conducting a current between the substrate and an anode to thereby deposit the matte layer on the surface of the substrate.
 47. The method of claim 46 wherein the deposition metal ions are selected from the group consisting of Fe, Co, Ni, Cu, Sn, Ag, and combinations thereof.
 48. The method of claim 46 wherein the at least one halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron is one or more from the group consisting of sodium methanesulfonate and hydrates thereof, potassium methanesulfonate and hydrates thereof, magnesium methanesulfonate and hydrates thereof, aluminum sulfate and hydrates thereof, or a boron tetrafluoride.
 49. The method of claim 46 wherein the at least one halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron is one or more from the group consisting of aluminum sulfates and hydrates thereof, sodium sulfates and hydrates, and magnesium sulfates and hydrates thereof, and any combination thereof.
 50. The method of claim 47 wherein the at least one halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron is one or more from the group consisting of sodium methanesulfonate and hydrates thereof, potassium methanesulfonate and hydrates thereof, magnesium methanesulfonate and hydrates thereof, aluminum sulfate and hydrates thereof, or a boron tetrafluoride.
 51. The method of claim 47 wherein the at least one halogenide, sulfate, or sulfonate of an element of the group consisting of sodium, potassium, aluminum, magnesium, or boron is one or more from the group consisting of aluminum sulfates and hydrates thereof, sodium sulfates and hydrates, and magnesium sulfates and hydrates thereof, and any combination thereof.
 52. The method of claim 46 wherein the electrolytic composition further comprises a surface active wetting agent selected from the group consisting of alkyl sulfates, sulfo-succinic acid, and betaines.
 53. The method of claim 46 wherein the matte layer is a nickel layer and the method comprises: exposing the surface of the substrate to an electrolytic nickel plating composition comprising at least about 10 g/L nickel ions and said auxiliary metal ion selected from the group consisting of sodium, potassium, magnesium, aluminum, boron, or combinations thereof, wherein a weight ratio of auxiliary metal ions to nickel metal ions is at least about 0.8:1; and conducting a current between the substrate and an anode to thereby deposit the matte nickel layer on the surface of the substrate.
 54. The method of claim 46 wherein the weight ratio of auxiliary metal ions to nickel ions is at least about 1:1.
 55. The method of claim 46 wherein the matte layer is a cobalt-tin layer and the method comprises: exposing the surface of the substrate to an electrolytic cobalt-tin alloy plating composition comprising at least about 10 g/L cobalt ions, at least about 10 g/L tin ions, and an auxiliary metal ion selected from the group consisting of sodium, potassium, magnesium, aluminum, boron, or combinations thereof, wherein a weight ratio of auxiliary metal ions to sum of the cobalt metal ions and the tin metal ions is at least about 0.2:1; and conducting a current between the substrate and an anode to thereby deposit the matte cobalt-tin alloy layer on the surface of the substrate. 